Flexible packaging has long been used to package products such as books, compact discs, cassette tapes, and a host of other types of objects to provide protection when shipping or mailing the objects, and in some cases to hermetically seal the objects from the outside environment. Web-handling machines have been developed to automate the process of packaging products in flexible packaging materials. Dual-web machines bring a pair of webs into generally parallel confronting relation with each other and feed a product, or a group of products, between the webs. At a downstream sealing station, the webs are sealed together around the product(s), thus forming a package containing the product(s). The package is severed from the remainder of the webs to complete the process. Single-web machines work similarly, except a single web is either supplied to the machine as a C-fold, or a flat web is manipulated and folded into a C-fold configuration, the objects to be packaged are inserted between the two opposing portions of the C-folded web, and one longitudinal seal and two cross seals are formed.
The web-handling machines typically are configured to operate continuously or manually. In a continuous mode, the machine's various motors and components are constantly running and driving the webs of material from their supply rolls through the nipping station and packaging any product placed between the webs. A continuous mode is often used when there is a continuous stream of products being placed between the webs to be packaged. Usually the continuous stream of products is delivered via an automatic conveying system, such as a conveyor belt.
A drawback of a continuous mode is the inevitable break in the continuous stream of products. For a variety of reasons, there will be unintended breaks in the stream of products being fed to the web-handling machine. When this happens while a machine is in continuous mode, the machine still advances the webs of material, but because of the missing product, portions of the webs of material are wasted. Also wasted are the energy and additional wear on the machine for running unnecessarily when no products are available for packaging.
In a manual mode, the various machine motors and components run only when an operator engages a selector switch, such as a cycle button. By hitting the cycle button, the machine is caused to operate through one cycle, wherein one product or set of products and portions of both webs are advanced through the sealing station to form a package. A manual mode is typically used when single products or relatively small batches of products are packaged and an operator physically places the products between the webs to be packaged.
Although a manual mode reduces possible wasted packaging material associated with a continuous mode, the manual mode also has its drawbacks. A primary drawback with a manual mode is the increase in the wear and tear in the machine's motors and components due to the multiple starts and short operating times that they must endure. Also, a manual mode does not eliminate wasted packaging material entirely. An operator may accidentally hit the cycle button and cause the machine to cycle without packaging a product, referred to herein as an empty cycle. Manual mode becomes more problematic if the products arrive in batches. In that case, an operator has to be present throughout the packaging of the entire batch in order to hit the cycle button between products. Even if the operator is able to select multiple cycles, this is not an entirely satisfactory solution because it increases the chances of running a cycle unnecessarily.
In light of the above considerations, a more versatile packaging machine and method are needed to prevent the machine from running unnecessarily and wasting packaging material and other resources.